准噶尔盆地永进油田侏罗系超深层致密砂岩储层成岩相识别及分布预测

深层致密砂岩储层非均质性强、分布规律复杂，地质甜点预测难度大。为实现高效勘探开发，如何准确识别与预测井间储层成岩相亟需深入研究。综合利用岩心、测井和三维地震资料，在准噶尔盆地永进油田侏罗系超深层储层成岩作用研究基础上，开展了成岩相识别及分布预测研究，认为储层成岩作用类型主要有压实作用、胶结作用及溶蚀与交代作用，可划分为强溶蚀+绿泥石包壳、中等溶蚀+自生高岭石、中等钙质胶结溶蚀、强钙质胶结及压实致密等5 种成岩相。基于测井资料，利用岩石物理参数、物性参数对储层成岩相类型进行了综合识别，确定其垂向分布规律。研究发现强溶蚀+绿泥石包壳和中等溶蚀+自生高岭石这两种优势成岩相主要位于三角洲主干分流河道砂体内部，储层物性较好，是油层发育的主要部位。基于成岩相与地震纵波阻抗的对应关系分析，发现优势成岩相纵波阻抗相对较低，可通过纵波阻抗的数值分布特征预测优势成岩相分布。因此利用三维地震纵波阻抗反演成果开展了成岩相分布预测，根据纵波阻抗与不同类型成岩相对应关系落实了优势成岩相发育区。结果表明，优势成岩相主要位于研究区东北部的Y301—Y302 井区以及西北部Y1 井区，呈局部连片分布发育。储层成岩相识别可以为超深层地质甜点的分布预测研究提供重要依据。

Diagenetic facies identification and distribution prediction of Jurassic ultra-deep tight sandstone reservoirs in Yongjin Oilfield，Junggar Basin

Deep-buried tight sandstone reservoirs have strong heterogeneity and complex distribution patterns， which makes it difficult to predict geological sweet spots in those reservoirs. In order to achieve efficient exploration and development， it is urgent to research the accurate identification and prediction of the diagenetic facies of reservoirs among the wells. The identification and distribution prediction of diagenetic facies were carried out using core， well logging， and 3D seismic data based on the diagenesis of Jurassic ultra-deep reservoirs in Yongjin Oilfield， Junggar Basin. It was considered that the diagenesis types of reservoirs mainly include compaction， cementation， dissolution， and metasomatism， which can be divided into five diagenetic facies， such as strong dissolution with chlorite enclave， medium dissolution with authigenic kaolinite， medium calcareous cemented dissolution， strong calcareous cementation， and strongly tight compaction. Based on logging data， petrophysical and physical parameters were used to identify diagenetic facies types of the reservoirs and determine their vertical distribution. The results find that the two dominant diagenetic facies， namely strong dissolution with chlorite enclave and medium dissolution with authigenic kaolinite， are mainly located in the sand body of the main distributary channel of the delta， with suitable reservoir property， and they are the main parts of the oil reservoir development. Based on the analysis of the corresponding relationship between diagenetic facies and seismic P-wave impedance， it is found that the P-wave impedance of the dominant diagenetic facies is relatively low， and the distribution of the dominant diagenetic facies can be predicted by the numerical distribution characteristics of P-wave impedance. Therefore，diagenetic facies distribution is predicted using the inversion results of 3D seismic P-wave impedance， and the development area of thedominant diagenetic facies is determined according to the corresponding relationship between P-wave impedance and different types of diagenetic rocks. The result indicates that the dominant diagenetic facies are mainly located in the Y301-Y302 well area in the northeast of the study area and the Y1 well area in the northwest， showing a locally continuous distribution pattern. Identification of diagenetic facies in reservoirs can provide an essential basis for the distribution prediction of ultra-deep geological sweet spots.